Feedthrough multilayer capacitor array

ABSTRACT

A feedthrough multilayer capacitor array having a capacitor body which has a plurality of insulator layers laminated, a first signal inner electrode connected to two first signal terminal electrodes, a second signal inner electrode connected to two second signal terminal electrodes, a first grounding inner electrode connected to one first grounding terminal electrode, and a second grounding inner electrode connected to one second grounding terminal electrode. The first signal inner electrode and second grounding inner electrode include respective portions opposing each other while holding therebetween at least one of the insulator layers. The second signal inner electrode and first grounding inner electrode include respective portions opposing each other while holding therebetween at least one of the insulator layers. The first and second signal inner electrodes include respective portions opposing each other while holding therebetween at least one of the insulator layers.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a feedthrough multilayer capacitorarray.

2. Related Background Art

Conventionally known as a feed through capacitor array is one in which aplurality of signal inner electrodes and a plurality of grounding innerelectrodes are laminated with insulator layers interposed therebetween,whereby a plurality of capacitors are formed along the laminatingdirection (see, for example, Japanese Patent Application Laid-Open No.HEI 11-97291).

SUMMARY OF THE INVENTION

In the feedthrough multilayer capacitor array described in JapanesePatent Application Laid-Open No. HEI 11-97291, however, onlycombinations of inner electrodes for signals and grounding formcapacitors. Therefore, only feedthrough capacitors are formed in thefeedthrough multilayer capacitor array described in Japanese PatentApplication Laid-Open No. HEI 11-97291. Hence, no consideration foreliminating both common-mode noise and differential-mode noise is madein the feedthrough multilayer capacitor array described in JapanesePatent Application Laid-Open No. HEI 11-97291.

It is an object of the present invention to provide a feedthroughmultilayer capacitor array which can eliminate both common-mode noiseand differential-mode noise.

The present invention provides a feedthrough multilayer capacitor arraycomprising a capacitor body, at least two first signal terminalelectrodes arranged on an outer surface of the capacitor body, at leasttwo second signal terminal electrodes arranged on the outer surface ofthe capacitor body, at least one first grounding terminal electrodearranged on the outer surface of the capacitor body, and at least onesecond grounding terminal electrode arranged on the outer surface of thecapacitor body; wherein the capacitor body has a plurality of insulatorlayers laminated, first and second signal inner electrodes, and firstand second grounding inner electrodes; wherein the first signal innerelectrode is connected to the at least two first signal terminalelectrodes; wherein the second signal inner electrode is connected tothe at least two second signal terminal electrodes; wherein the firstgrounding inner electrode is connected to the at least one firstgrounding terminal electrode; wherein the second grounding innerelectrode is connected to the at least one second grounding terminalelectrode; wherein the first signal inner electrode and second groundinginner electrode include respective portions opposing each other whileholding therebetween at least one of the plurality of insulator layers;wherein the second signal inner electrode and first grounding innerelectrode include respective portions opposing each other while holdingtherebetween at least one of the plurality of insulator layers; andwherein the first and second signal inner electrodes include respectiveportions opposing each other while holding therebetween at least one ofthe plurality of insulator layers.

The above-mentioned feedthrough multilayer capacitor array has not onlycapacitors formed by signal and grounding inner electrodes opposing eachother, but also capacitors formed by signal inner electrodes opposingeach other. The capacitors formed by the signal and grounding innerelectrodes function as capacitors for eliminating common-mode noise. Onthe other hand, the capacitors formed by the signal inner electrodesfunction as capacitors for eliminating differential-mode noise.Therefore, this feedthrough multilayer capacitor array can eliminateboth common-mode noise and differential-mode noise. Since all the signalinner electrodes penetrate through the array, namely all the signalinner electrodes are connected to two terminal electrodes respectively,equivalent series inductance (ESL) can be lowered. Also, in thisfeedthrough multilayer capacitor array, the first and second signalinner electrodes have respective portions opposing each other whileholding an insulator layer therebetween. As a consequence, current flowpaths increase as compared with the case where the first and secondsignal inner electrodes do not oppose each other while holding aninsulator layer therebetween as in the conventional capacitor array.This can reduce the equivalent series inductance.

Preferably, the first signal inner electrode and first grounding innerelectrode are arranged on the same insulator layer in the plurality ofinsulator layers, the second signal inner electrode and second groundinginner electrode are arranged on the same insulator layer in theplurality of insulator layers, and the insulator layer having the firstsignal inner electrode and first grounding inner electrode arrangedthereon and the insulator layer having the second signal inner electrodeand second grounding inner electrode arranged thereon differ from eachother. In this case, it becomes feasible to manufacture a feedthroughmultilayer capacitor array by forming a conductor pattern correspondingto both the signal and grounding inner electrodes on one ceramic greensheet. Therefore, the feedthrough multilayer capacitor array can bemanufactured efficiently.

Preferably, the at least one insulator layer held between the firstsignal inner electrode and second grounding inner electrode, the atleast one insulator layer held between the second signal inner electrodeand first grounding inner electrode, and the at least one insulatorlayer held between the first and second signal inner electrodes are thesame. In this case, the first and second signal inner electrodes and thefirst and second grounding inner electrodes are arranged such as to holdthe same insulator layer therebetween, whereby characteristics ofcapacitors included in the feedthrough multilayer capacitor array can beregulated easily.

Preferably, one of the at least two first signal terminal electrodes andone of the at least two second signal terminal electrodes are arrangedon the same side face in the outer surface of the capacitor body, whilethe other of the at least two first signal terminal electrodes and theother of the at least two second signal terminal electrodes are arrangedon the same side face in the outer surface of the capacitor body. Whenthe first and second signal terminal electrodes are connected toheteropolar land patterns and the like in this case, the current flowingthrough the first signal inner electrode and the current flowing throughthe second signal inner electrode can be directed opposite to eachother. This can reduce the equivalent series inductance.

Preferably, at least three each of the first and second signal terminalelectrodes are provided, the first signal inner electrode is connectedto the at least three first signal terminal electrodes, and the secondsignal inner electrode is connected to the at least three second signalterminal electrodes. This increases paths for currents flowing into andout of the signal inner electrodes, thereby further reducing theequivalent series inductance.

The present invention can provide a feedthrough multilayer capacitorarray which can eliminate both common-mode noise and differential-modenoise.

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not to beconsidered as limiting the present invention.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the feedthrough multilayer capacitorarray in accordance with a first embodiment;

FIG. 2 is an exploded perspective view of the capacitor body included inthe feedthrough multilayer capacitor array in accordance with the firstembodiment;

FIG. 3 is a view for explaining the fact that the inner electrodes ownedby the capacitor body have portions opposing each other;

FIG. 4 is an equivalent circuit diagram of the feedthrough multilayercapacitor array in accordance with the first embodiment;

FIG. 5 is a diagram showing an example in which the feedthroughmultilayer capacitor array in accordance with the first embodiment isconnected to a circuit;

FIG. 6 is an equivalent circuit diagram in the case where thefeedthrough multilayer capacitor array is connected to a circuit asshown in FIG. 5;

FIG. 7 is a diagram showing an example in which the feedthroughmultilayer capacitor array in accordance with the first embodiment isconnected to a circuit;

FIG. 8 is an equivalent circuit diagram in the case where thefeedthrough multilayer capacitor array is connected to a circuit asshown in FIG. 7;

FIG. 9 is an exploded perspective view of the capacitor body included ina modified example of the feedthrough multilayer capacitor array inaccordance with the first embodiment;

FIG. 10 is a perspective view of the feedthrough multilayer capacitorarray in accordance with a second embodiment;

FIG. 11 is an exploded perspective view of the capacitor body includedin the feedthrough multilayer capacitor array in accordance with thesecond embodiment; and

FIG. 12 is a view for explaining the fact that the inner electrodesowned by the capacitor body have portions opposing each other

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, preferred embodiments will be explained in detail withreference to the accompanying drawings. In the explanation, the sameconstituents or those having the same functions will be referred to withthe same numerals while omitting their overlapping descriptions.

First Embodiment

With reference to FIGS. 1 and 2, the structure of feedthrough multilayercapacitor array CA1 in accordance with a first embodiment will beexplained. FIG. 1 is a perspective view of the feedthrough multilayercapacitor array in accordance with the first embodiment. FIG. 2 is anexploded perspective view of the capacitor body included in thefeedthrough multilayer capacitor array in accordance with the firstembodiment.

As shown in FIG. 1, the feedthrough multilayer capacitor array CA1comprises a capacitor body L1 having a substantially rectangularparallelepiped form, first and second signal terminal electrodes 1A, 1B,2A, 2B formed on the outer surface of the capacitor body L1, and firstand second grounding terminal electrodes 3, 4. The capacitor body L1includes first and second side faces L1 a, L1 b opposing each other andcorresponding to main faces of the substantially rectangularparallelepiped, third and fourth side faces L1 c, L1 d opposing eachother and extending along the shorter side direction of the first andsecond side faces L1 a, L1 b, and fifth and sixth side faces L1 e, L1 fopposing each other and extending in the longer side direction of thefirst and second side faces L1 a, L1 b. The third and fourth side facesL1 c, L1 d and the fifth and sixth side faces L1 e, L1 f extend so as toconnect the first and second side faces L1 a and L1 b to each other.

The fifth side face L1 e of the capacitor body L1 is formed with thefirst signal terminal electrode 1A and the second signal terminalelectrode 2A. The first signal terminal electrode 1A and second signalterminal electrode 2A are positioned in the order of the first signalterminal electrode 1A and second signal terminal electrode 2A in thedirection from the third side face L1 c to the fourth side face L1 d.The sixth side face L1 f of the capacitor body L1 is formed with thefirst signal terminal electrode 1B and the second signal terminalelectrode 2B. The first signal terminal electrode 1B and second signalterminal electrode 2B are positioned in the order of the first signalterminal electrode 1B and second signal terminal electrode 2B in thedirection from the third side face L1 c to the fourth side face L1 d.

The first signal terminal electrodes 1A, 1B oppose each other in thedirection in which the fifth and sixth side faces L1 e, L1 f oppose eachother. The second signal terminal electrodes 2A, 2B oppose each other inthe direction in which the fifth and sixth side faces L1 e, L1 f opposeeach other.

The third side face L1 c of the capacitor body L1 is formed with thesecond grounding terminal electrode 4. The fourth side face L1 d of thecapacitor body L1 is formed with the first grounding terminal electrode3. The first and second grounding terminal electrodes 3, 4 oppose eachother in the direction in which the third and fourth side faces L1 c, L1d oppose each other.

Each of the first and second signal terminal electrodes 1A, 1B, 2A, 2Band first and second grounding terminal electrodes 3, 4 is formed, forexample, by applying and baking a conductive paste, which contains aconductive metal powder and a glass frit, onto the outer surface of thecapacitor body L1. A plating layer may be formed on the baked electrodeswhen necessary.

The capacitor body L1 has a plurality of (3 in this embodiment)insulator layers 10 to 12 laminated, a first signal inner electrode 20,a first grounding inner electrode 40, a second signal inner electrode30, and a second grounding inner electrode 50. Each of the insulatorlayers 10 to 12 extends in a direction parallel to the first and secondside faces L1 a, L1 b. In the capacitor body L1, the first side face L1a and second side face L1 b oppose each other in the laminatingdirection of the plurality of insulator layers 10 to 12.

Each of the insulator layers 10 to 12 is constituted by a sintered bodyof a ceramic green sheet including a dielectric ceramic, for example. Inthe actual feedthrough multilayer capacitor array CA1, the insulatorlayers 10 to 12 are integrated to such an extent that their boundariesare indiscernible. Each of the inner electrodes 20, 30, 40, 50 isconstituted by a sintered body of a conductive paste.

The first signal inner electrode 20 and second grounding inner electrode50 are arranged such as to include respective portions opposing eachother while holding therebetween the insulator layer 11, which is one ofthe plurality of insulator layers 10 to 12. The second signal innerelectrode 30 and first grounding inner electrode 40 are arranged such asto include respective portions opposing each other while holdingtherebetween the insulator layer 11, which is one of the plurality ofinsulator layers 10 to 12. The first and second signal inner electrodes20, 30 are arranged such as to include respective portions opposing eachother while holding therebetween the insulator layer 11, which is one ofthe plurality of insulator layers 10 to 12.

As shown in FIG. 2, the first signal inner electrode 20 is arrangedwithin the same plane as the first grounding inner electrode 40. Namely,the first signal inner electrode 20 and first grounding inner electrode40 are arranged on the same insulator layer 11 in the plurality ofinsulator layers 10 to 12. While being separated by a predetermineddistance from each other, the first signal inner electrode 20 and firstgrounding inner electrode 40 are arranged in a row in the direction inwhich the third side face L1 c and fourth side face L1 d oppose eachother. The first signal inner electrode 20 and first grounding innerelectrode 40 are electrically insulated from each other.

As shown in FIG. 2, the second signal inner electrode 30 is arrangedwithin the same plane as the second grounding inner electrode 50.Namely, the second signal inner electrode 30 and second grounding innerelectrode 50 are arranged on the same insulator layer 12 in theplurality of insulator layers 10 to 12. The second signal innerelectrode 30 and second grounding inner electrode 50 are arranged on theinsulator layer 12 different from the insulator layer 11 on which thefirst signal inner electrode 20 and first grounding inner electrode 40are arranged. While being separated by a predetermined distance fromeach other, the second signal inner electrode 30 and second groundinginner electrode 50 are arranged in a row in the direction in which thethird side face L1 c and fourth side face L1 d oppose each other. Thesecond signal inner electrode 30 and second grounding inner electrode 50are electrically insulated from each other.

The same insulator layer 11 is held between the first signal innerelectrode 20 and second grounding inner electrode 50, between the secondsignal inner electrode 30 and first grounding inner electrode 40, andbetween the first and second signal inner electrodes 20, 30.

The first signal inner electrode 20 includes a main electrode portion 21having a quadrangular form whose four sides are parallel to the third,fourth, fifth, and sixth side faces L1 c, L1 d, L1 e, L1 f,respectively, a lead portion 22 extending from the main electrodeportion 21 so as to reach the fifth side face L1 e, and a lead portion23 extending from the main electrode portion 21 so as to reach the sixthside face L1 f. The first signal inner electrode 20 penetrates throughthe capacitor body L1 from the fifth side face L1 e to the sixth sideface L1 f.

The main electrode portion 21 is separated not only from the firstgrounding inner electrode 40 by a predetermined distance as mentionedabove, but also from the third, fourth, fifth, and sixth side faces L1c, L1 d, L1 e, L1 f by predetermined distances. The lead portion 22 isdrawn to the fifth side face L1 e, so as to be connected to the firstsignal terminal electrode 1A electrically and physically. The leadportion 23 is drawn to the sixth side face L1 f, so as to be connectedto the first signal terminal electrode 1B electrically and physically.As a consequence, the first signal inner electrode 20 is electricallyconnected to the first signal terminal electrodes 1A, 1B.

The first grounding inner electrode 40 includes a quadrangular mainelectrode portion 41 whose four sides are parallel to the third, fourth,fifth, and sixth side faces L1 c, L1 d, L1 e, L1 f, respectively, and alead portion 42 extending from the main electrode portion 41 so as toreach the fourth side face L1 d.

The main electrode portion 41 is separated not only from the firstsignal inner electrode 20 by a predetermined distance as mentionedabove, but also from the third, fourth, fifth, and sixth side faces L1c, L1 d, L1 e, L1 f by predetermined distances. The lead portion 42 isdrawn to the fourth side face L1 d, so as to be connected to the firstgrounding terminal electrode 3 electrically and physically. As aconsequence, the first grounding inner electrode 40 is electricallyconnected to the first grounding terminal electrode 3.

The second signal inner electrode 30 includes a quadrangular mainelectrode portion 31 whose four sides are parallel to the third, fourth,fifth, and sixth side faces L1 c, L1 d, L1 e, L1 f, a lead portion 32extending from the main electrode portion 31 so as to reach the fifthside face L1 e, and a lead portion 33 extending from the main electrodeportion 31 so as to reach the sixth side face L1 f. The second signalinner electrode 30 penetrates through the capacitor body L1 from thefifth side face L1 e to the sixth side face L1 f.

The main electrode portion 31 is separated not only from the secondgrounding inner electrode 50 by a predetermined distance as mentionedabove, but also from the third, fourth, fifth, and sixth side faces L1c, L1 d, L1 e, L1 f by predetermined distances. The lead portion 32 isdrawn to the fifth side face L1 e, so as to be connected to the secondsignal terminal electrode 2A electrically and physically. The leadportion 33 is drawn to the sixth side face L1 f, so as to be connectedto the second signal terminal electrode 2B electrically and physically.As a consequence, the second signal inner electrode 30 is electricallyconnected to the second signal terminal electrodes 2A, 2B.

The second grounding inner electrode 50 includes a quadrangular mainelectrode portion 51 whose four sides are parallel to the third, fourth,fifth, and sixth side faces L1 c, L1 d, L1 e, L1 f, respectively, and alead portion 52 extending from the main electrode portion 51 so as toreach the third side face L1 c.

The main electrode portion 51 is separated not only from the secondsignal inner electrode 30 by a predetermined distance as mentionedabove, but also from the third, fourth, fifth, and sixth side faces L1c, L1 d, L1 e, L1 f by predetermined distances. The lead portion 52 isdrawn to the third side face L1 c, so as to be connected to the secondgrounding terminal electrode 4 electrically and physically. As aconsequence, the second grounding inner electrode 50 is electricallyconnected to the second grounding terminal electrode 4.

The fact that the inner electrodes 20, 30, 40, 50 owned by the capacitorbody L1 have portions opposing each other will be explained withreference to FIG. 3. FIG. 3 is a view for explaining the fact that theinner electrodes 20, 30, 40, 50 owned by the capacitor body L1 haveportions opposing each other.

As shown in FIG. 3, the main electrode portion 21 of the first signalinner electrode 20 and the main electrode portion 51 of the secondgrounding inner electrode 50 have respective portions opposing eachother while holding the insulator layer 11 therebetween. The portions bywhich the first signal inner electrode 20 and the second grounding innerelectrode 50 oppose each other form a first capacitor C1.

As shown in FIG. 3, the main electrode portion 31 of the second signalinner electrode 30 and the main electrode portion 41 of the firstgrounding inner electrode 40 have respective portions opposing eachother while holding the insulator layer 11 therebetween. The portions bywhich the second signal inner electrode 30 and the first grounding innerelectrode 40 oppose each other form a second capacitor C2.

As shown in FIG. 3, the main electrode portion 21 of the first signalinner electrode 20 and the main electrode portion 31 of the secondsignal inner electrode 30 have respective portions opposing each otherwhile holding the insulator layer 11 therebetween. The portions by whichthe first and second signal inner electrodes 20, 30 oppose each otherform a third capacitor C3.

Thus, three capacitors C1, C2, C3 are formed in the feedthroughmultilayer capacitor array CA1 as shown in FIG. 4. FIG. 4 is anequivalent circuit diagram of the feedthrough multilayer capacitor arrayin accordance with the first embodiment.

FIG. 5 shows an example in which the feedthrough multilayer capacitorarray CA1 is connected to a circuit. In the example shown in FIG. 5, thefeedthrough multilayer capacitor array CA1 is connected to lines 73, 74branching out of main lines 71, 72, respectively. Specifically, thefirst signal terminal electrodes 1A, 1B are connected to the line 73,while the second signal terminal electrodes 2A, 2B are connected to thelead 74. The first and second grounding terminal electrodes 3, 4 aregrounded.

Currents I₁, I₂ flow through the main lines 71, 72, respectively.Currents I₁₂, I₂₂ flow through the branch lines 73, 74, respectively.Currents I₁₁, I₂₁ flow through the main leads 71, 72 downstream theirbranch points, respectively. In this case, there is a current I₁₃flowing back from the main lead 71 to the lead 73 at the branch pointbetween the leads 71 and 73. On the other hand, there is a current I₂₃flowing back from the main lead 72 to the lead 74 at the branch pointbetween the leads 72 and 74. FIG. 6 shows an equivalent circuit diagramin the case where the feedthrough multilayer capacitor array CA1 isconnected to the circuit as shown in FIG. 5. This example of connectionis suitable in cases where large currents flow.

FIG. 7 shows another example in which the feedthrough multilayercapacitor array CA1 is connected to a circuit. In the example shown inFIG. 7, the feedthrough multilayer capacitor array CA1 is connected tomain lines 71, 72 having no branches. Specifically, the first signalterminal electrodes 1A, 1B are connected to the line 71, while thesecond signal terminal electrodes 2A, 2B are connected to the line 72.The first and second grounding terminal electrodes 3, 4 are grounded.Currents I₁, I₂ flow through the main leads 71, 72, respectively. FIG. 8shows an equivalent circuit diagram in the case where the feedthroughmultilayer capacitor array CA1 is connected to the circuit as shown inFIG. 7.

The feedthrough multilayer capacitor array CA1 has not only the firstcapacitor C1 formed by the first signal inner electrode 20 and secondgrounding inner electrode 50 opposing each other and the secondcapacitor C2 formed by the second signal inner electrode 30 and firstgrounding inner electrode 40 opposing each other, but also the thirdcapacitor C3 formed by the first and second signal inner electrodes 20,30 opposing each other. The first and second capacitors C1, C2 formed bythe signal inner electrodes 20, 30 and grounding inner electrodes 40, 50function as capacitors for eliminating common-mode noise. On the otherhand, the third capacitor C3 formed by the first and second signal innerelectrodes 20, 30 functions as a capacitor for eliminatingdifferential-mode noise. Therefore, the feedthrough multilayer capacitorarray CA1 can eliminate both common-mode noise and differential-modenoise.

Since each of the first and second signal inner electrodes 20, 30penetrates through the feedthrough multilayer capacitor array CA1,namely each of the first and second signal inner electrodes 20, 30 isconnected to the corresponding two signal terminal electrodes,equivalent series inductance (ESL) can be lowered.

In the feedthrough multilayer capacitor array CA1, the first and secondsignal inner electrodes 20, 30 have respective portions opposing eachother while holding the insulator layer 11 therebetween. This canincrease current flow paths as compared with the case where the firstand second signal inner electrodes do not oppose each other whileholding an insulator layer therebetween as in the conventional capacitorarray. As a consequence, the feedthrough multilayer capacitor array CA1can reduce the equivalent series inductance.

In particular, the feedthrough multilayer capacitor array CA1 has twokinds of grounding inner electrodes 40, 50 which oppose theircorresponding signal inner electrodes 20, 30. This further increases thecurrent flow paths, whereby the feedthrough multilayer capacitor arrayCA1 can further reduce the equivalent series inductance.

The first signal inner electrode 20 and first grounding inner electrode40 are positioned on the same insulator layer 11. The second signalinner electrode 30 and second grounding inner electrode 50 arepositioned on the same insulator layer 12. Therefore, when each of theinsulator layers 10 to 12 is constituted by a sintered body of a ceramicgreen sheet, for example, the first signal inner electrode 20 and firstgrounding inner electrode 40 can be formed on the same ceramic greensheet by a conductive paste, and the second signal inner electrode 30and second grounding inner electrode 50 can be formed on the sameceramic green sheet by a conductive paste. Namely, only two kinds ofceramic green sheets with conductor patterns are needed to be preparedfor making the capacitor body L1 having four kinds of inner electrodes20, 30, 40, 50. As a result, the capacitor body L1 can be manufacturedefficiently.

The same insulator layer 11 is held between the first signal innerelectrode 20 and second grounding inner electrode 50, between the secondsignal inner electrode 30 and first grounding inner electrode 40, andbetween the first and second signal inner electrodes 20, 30. Since thesame insulator layer 11 constitutes the capacitors C1, C2, C3 includedin the feedthrough multilayer capacitor array CA1, characteristics ofthe capacitors C1, C2, C3 can be regulated easily.

The first signal terminal electrode 1A and second signal terminalelectrode 2A are arranged on the fifth side face L1 e, which is the sameside face of the capacitor body L1. The first signal terminal electrode1B and second signal terminal electrode 2B are arranged on the sixthside face L1 f, which is the same side face of the capacitor body L1.Therefore, when the first signal terminal electrodes 1A, 1B and secondsignal terminal electrodes 2A, 2B are connected to heteropolar landpatterns and the like, the current flowing through the first signalinner electrode 20 and the current flowing through the second signalinner electrode 30 are directed opposite to each other. Also, the firstsignal inner electrode 20 and second signal inner electrode 30 opposeeach other while holding the insulator layer 11 therebetween. Therefore,a magnetic field obtained by the current flowing through the firstsignal inner electrode 20 and a magnetic field obtained by the currentflowing through the second signal inner electrode 30 cancel each otherout, whereby equivalent series inductance can be reduced.

The structure of a modified example of the feedthrough multilayercapacitor array CA1 in accordance with the first embodiment will now beexplained with reference to FIG. 9. FIG. 9 is an exploded perspectiveview of the capacitor body L1 included in the modified example of thefeedthrough multilayer capacitor array in accordance with the firstembodiment. The feedthrough multilayer capacitor array in accordancewith the modified example shown in FIG. 9 differs from the feedthroughmultilayer capacitor array CA1 in accordance with the above-mentionedfirst embodiment in that the first and second grounding inner electrodesare formed integrally.

The capacitor body L1 included in the feedthrough multilayer capacitorarray in accordance with the modified example has a plurality of (4 inthis embodiment) insulator layers 10 to 13 laminated, a first signalinner electrode 20, a second signal inner electrode 30, and first andsecond grounding inner electrodes 40, 50 formed integrally.

The first signal inner electrode 20 and second grounding inner electrode50 have respective portions opposing each other while holding theinsulator layers 11, 12 therebetween. The second signal inner electrode30 and first grounding inner electrode 40 have respective portionsopposing each other while holding the insulator layer 12 therebetween.The first and second signal inner electrodes 20, 30 have respectiveportions opposing each other while holding the insulator layer 11therebetween.

In the first and second grounding inner electrodes 40, 50 formedintegrally, the main electrode portions 41, 51 of the grounding innerelectrodes 40, 50 are integrated, so as to yield a quadrangular formwhose four sides are parallel to the third, fourth, fifth, and sixthside faces L1 c, L1 d, L1 e, L1 f, respectively. The integrally formedfirst and second grounding inner electrodes 40, 50 penetrate through thecapacitor body L1 from the third side face L1 c to the fourth side faceL1 d and are connected to the two grounding terminal electrodes 3, 4.

Second Embodiment

With reference to FIGS. 10 and 11, the structure of feedthroughmultilayer capacitor array CA2 in accordance with a second embodimentwill be explained. The feedthrough multilayer capacitor array CA2 inaccordance with the second embodiment differs from the feedthroughmultilayer capacitor array CA1 in accordance with the first embodimentin terms of the number of signal terminal electrodes in each species.FIG. 10 is a perspective view of the feedthrough multilayer capacitorarray in accordance with the second embodiment. FIG. 11 is an explodedperspective view of the capacitor body included in the feedthroughmultilayer capacitor array in accordance with the second embodiment.

As shown in FIG. 10, the feedthrough multilayer capacitor array CA2comprises a capacitor body L2, and first and second signal terminalelectrodes 1A to 1D, 2A to 2D and first and second grounding terminalelectrodes 3, 4 which are formed on the outer surface of the capacitorbody L2.

The capacitor body L2 includes first and second side faces L2 a, L2 bopposing each other and corresponding to main faces of a substantiallyrectangular parallelepiped, third and fourth side faces L2 c, L2 dopposing each other and extending in the shorter side direction of thefirst and second side faces L2 a, L2 b, and fifth and sixth side facesL2 e, L2 f opposing each other and extending in the longer sidedirection of the first and second side faces L2 a, L2 b.

The fifth side face L2 e of the capacitor body L2 is formed with firstsignal terminal electrodes 1A, 1B and second signal terminal electrodes2A, 2B. The first signal terminal electrodes 1A, 1B and second signalterminal electrodes 2A, 2B are positioned in the order of the secondsignal terminal electrode 2A, first signal terminal electrode 1A, secondsignal terminal electrode 2B, and first signal terminal electrode 1B inthe direction from the third side face L2 c to the fourth side face 2 d.

The sixth side face L2 f of the capacitor body L2 is formed with firstsignal terminal electrodes 1C, 1D and second signal terminal electrodes2C, 2D. The first signal terminal electrodes 1C, 1D and second signalterminal electrodes 2C, 2D are positioned in the order of the secondsignal terminal electrode 2C, first signal terminal electrode 1C, secondsignal terminal electrode 2D, and first signal terminal electrode 1D inthe direction from the third side face L2 c to the fourth side face L2d.

The first signal terminal electrodes 1A, 1C oppose each other in thedirection in which the fifth and sixth side faces L2 e, L2 f oppose eachother. The first signal terminal electrodes 1B, 1D oppose each other inthe direction in which the fifth and sixth side faces L2 e, L2 f opposeeach other. The second signal terminal electrodes 2A, 2C oppose eachother in the direction in which the fifth and sixth side faces L2 e, L2f oppose each other. The second signal terminal electrodes 2B, 2D opposeeach other in the direction in which the fifth and sixth side faces L2e, L2 f oppose each other.

As with the first and second signal terminal electrodes 1A, 1B, 2A, 2Band first and second grounding terminal electrodes 3, 4, the first andsecond signal terminal electrodes 1C, 1D, 2C, 2D are formed, forexample, by applying and baking a conductive paste, which contains aconductive metal powder and a glass frit, onto the outer surface of thecapacitor body L2. A plating layer may be formed on the baked electrodeswhen necessary.

As shown in FIG. 2, the capacitor body L2 has a plurality of (3 in thisembodiment) insulator layers 10 to 12 laminated, a first signal innerelectrode 20, a first grounding inner electrode 40, a second signalinner electrode 30, and a second grounding inner electrode 50.

The first signal inner electrode 20 includes a main electrode portion 21having a substantially quadrangular form whose four sides are parallelto the third, fourth, fifth, and sixth side faces L2 c, L2 d, L2 e, L2f, respectively, lead portions 22, 23 extending from the main electrodeportion 21 so as to reach the fifth side face L2 e, and lead portions24, 25 extending from the main electrode portion 21 so as to reach thesixth side face L2 f. The first signal inner electrode 20 penetratesthrough the capacitor body L2 from the fifth side face L2 e to the sixthside face L2 f.

A portion of a side of the main electrode portion 21 parallel to thefourth side face L2 d is formed with a recess 26 toward the third sideface L2 c. The lead portion 22 is drawn to the fifth side face L2 e, soas to be connected to the first signal terminal electrode 1Aelectrically and physically. The lead portion 23 is drawn to the fifthside face L2 e, so as to be connected to the first signal terminalelectrode 1B electrically and physically. The lead portion 24 is drawnto the sixth side face L2 f, so as to be connected to the first signalterminal electrode 1C electrically and physically. The lead portion 25is drawn to the sixth side face L2 f, so as to be connected to the firstsignal terminal electrode 1D electrically and physically. As aconsequence, the first signal inner electrode 20 is electricallyconnected to the first signal terminal electrodes 1A to 1D.

The first grounding inner electrode 40 includes a main electrode portion41 having a quadrangular form whose four sides are parallel to thethird, fourth, fifth, and sixth side faces L2 c, L2 d, L2 e, L2 f,respectively, and a lead portion 42 extending from the main electrodeportion 41 so as to reach the fourth side face L2 d.

The main electrode portion 41 is separated from the third, fourth,fifth, and sixth side faces L2 c, L2 d, L2 e, L2 f by predetermineddistances. The lead portion 42 has the same width as that of the mainelectrode portion 41 in the direction in which the fifth and sixth sidefaces L2 e, L2 f oppose each other. Therefore, the main electrodeportion 41 and lead portion 42 are integrated, so as to yield aquadrangular form. The lead portion 42 is drawn to the fourth side faceL2 d, so as to be connected to the first grounding terminal electrode 3electrically and physically. As a consequence, the first grounding innerelectrode 40 is electrically connected to the first grounding terminalelectrode 3.

The second signal inner electrode 30 includes a main electrode portion31 having a substantially quadrangular form whose four sides areparallel to the third, fourth, fifth, and sixth side faces L2 c, L2 d,L2 e, L2 f, respectively, lead portions 32, 33 extending from the mainelectrode portion 31 so as to reach the fifth side face L2 e, and leadportions 34, 35 extending from the main electrode portion 31 so as toreach the sixth side face L2 f. The second signal inner electrode 30penetrates through the capacitor body L2 from the fifth side face L2 eto the sixth side face L2 f.

A portion of a side of the main electrode portion 31 parallel to thethird side face L2 c is formed with a recess 36 toward the fourth sideface L2 d. The lead portion 32 is drawn to the fifth side face L2 e, soas to be connected to the second signal terminal electrode 2Aelectrically and physically. The lead portion 33 is drawn to the fifthside face L2 e, so as to be connected to the second signal terminalelectrode 2B electrically and physically. The lead portion 34 is drawnto the sixth side face L2 f, so as to be connected to the second signalterminal electrode 2C electrically and physically. The lead portion 35is drawn to the sixth side face L2 f, so as to be connected to thesecond signal terminal electrode 2D electrically and physically. As aconsequence, the second signal inner electrode 30 is electricallyconnected to the second signal terminal electrodes 2A to 2D.

The second grounding inner electrode 50 includes a quadrangular mainelectrode portion 51 whose four sides are parallel to the third, fourth,fifth, and sixth side faces L2 c, L2 d, L2 e, L2 f, respectively, and alead portion 52 extending from the main electrode portion 51 so as toreach the fourth side face L2 d.

The main electrode portion 51 is separated from the third, fourth,fifth, and sixth side faces L2 c, L2 d, L2 e, L2 f by predetermineddistances. The lead portion 52 has the same width as that of the mainelectrode portion 51 in the direction in which the fifth and sixth sidefaces L2 e, L2 f oppose each other. Therefore, the main electrodeportion 51 and the lead portion 52 are integrated together to yield aquadrangular form. The lead portion 52 is drawn to the third side faceL2 c, so as to be connected to the second grounding terminal electrode 4electrically and physically. As a consequence, the second groundinginner electrode 50 is electrically connected to the second groundingterminal electrode 4.

The first grounding inner electrode 40 is arranged such that the mainelectrode portion 41 is positioned within the recess 26 formed in theside on the fourth side face L2 d side of the first signal innerelectrode 20. The second grounding inner electrode 50 is arranged suchthat the main electrode portion 51 is positioned within the recess 36formed in the side on the third side face L2 c side of the second signalinner electrode 30.

The fact that the inner electrodes 20, 30, 40, 50 owned by the capacitorbody L2 have portions opposing each other will be explained withreference to FIG. 12. FIG. 12 is a view for explaining the fact that theinner electrodes 20, 30, 40, 50 owned by the capacitor body L1 haveportions opposing each other.

As shown in FIG. 12, the portions by which the first signal innerelectrode 20 and the second grounding inner electrode 50 oppose eachother form a first capacitor C1. The portions by which the second signalinner electrode 30 and the first grounding inner electrode 40 opposeeach other form a second capacitor C2. The portions by which the firstand second signal inner electrodes 20, 30 oppose each other form a thirdcapacitor C3. Thus, three capacitors C1, C2, C3 are formed in thefeedthrough multilayer capacitor array CA2 as shown in FIG. 12.

In the second embodiment, as in the foregoing like the above-mentionedfirst embodiment, the feedthrough multilayer capacitor array CA2 has notonly the first and second capacitors C1, C2 formed by the fact that thesignal inner electrodes 20, 30 oppose their corresponding groundinginner electrodes 40, 50, but also the third capacitor C3 formed by thesignal inner electrodes 20, 30 opposing each other. The first and secondcapacitors C1, C2 function as capacitors for eliminating common-modenoise. On the other hand, the third capacitor C3 functions as acapacitor for eliminating differential-mode noise. Therefore, thefeedthrough multilayer capacitor array CA3 can eliminate bothcommon-mode noise and differential-mode noise.

Since each of the first and second signal inner electrodes 20, 30penetrates through the feedthrough multilayer capacitor array CA2,equivalent series inductance (ESL) can be lowered.

In the feedthrough multilayer capacitor array CA2, the first and secondsignal inner electrodes 20, 30 have respective portions opposing eachother while holding the insulator layer 11 therebetween. Therefore,current flow paths become greater than conventional ones. As aconsequence, the feedthrough multilayer capacitor array CA2 can reducethe equivalent series inductance.

In particular, the feedthrough multilayer capacitor array CA2 has twokinds of grounding inner electrodes 40, 50 which oppose theircorresponding signal inner electrodes 20, 30. This further increases thecurrent flow paths, whereby the feedthrough multilayer capacitor arrayCA1 can further reduce the equivalent series inductance.

The first signal inner electrode 20 and first grounding inner electrode40 are positioned between the same two insulator layers 10, 11. Thesecond signal inner electrode 30 and second grounding inner electrode 50are positioned between the same two insulator layers 11, 12. Therefore,they can be manufactured efficiently.

The first signal inner electrode 20 and first grounding inner electrode40 are positioned on the same insulator layer 11. The second signalinner electrode 30 and second grounding inner electrode 50 arepositioned on the same insulator layer 12. Therefore, the feedthroughmultilayer capacitor array CA2 can be manufactured efficiently as withthe feedthrough multilayer capacitor array CA1 in accordance with theabove-mentioned first embodiment.

The same insulator layer 11 is held between the first signal innerelectrode 20 and second grounding inner electrode 50, between the secondsignal inner electrode 30 and first grounding inner electrode 40, andbetween the first and second signal inner electrodes 20, 30. In thiscase, characteristics of the capacitors C1, C2, C3 included in thefeedthrough multilayer capacitor array CA2 can be regulated easily.

The first signal terminal electrodes 1A, 1B and the second signalterminal electrodes 2A, 2B are arranged on the fifth side face L2 e,which is the same side face of the capacitor body L2. The first signalterminal electrodes 1C, 1D and the second signal terminal electrodes 2C,2D are arranged on the sixth side face L2 f, which is the same side faceof the capacitor body L2. Therefore, when the first signal terminalelectrodes 1A, 1B and second signal terminal electrodes 2A, 2B areconnected to heteropolar land patterns and the like, the current flowingthrough the first signal inner electrode 20 and the current flowingthrough the second signal inner electrode 30 are directed opposite toeach other. Also, the first signal inner electrode 20 and second signalinner electrode 30 oppose each other while holding the insulator layer11 therebetween. Therefore, equivalent series inductance can be reduced.

The first and second signal terminal electrodes 1A to 1D, 2A to 2D areprovided four by four. The signal inner electrodes 20, 30 include fourlead portions 22 to 25, 32 to 35, respectively. This increases paths forcurrents flowing into and out of the signal inner electrodes 20, 30,thereby further reducing the equivalent series inductance in thefeedthrough multilayer capacitor array CA2.

Though preferred embodiments of the present invention are explained inthe foregoing, the present invention is not necessarily restricted tothe above-mentioned embodiments and modified example, but can be alteredin various ways within the scope not deviating from the gist thereof.

Though the first signal inner electrode 20 and first grounding innerelectrode 40 are arranged on the same insulator layer in theabove-mentioned embodiments, this is not restrictive. For example, thefirst signal inner electrode 20 and first grounding inner electrode 40may be arranged on different insulator layers, i.e., at differentpositions in the laminating direction of the insulator layers 10 to 12.Though the second signal inner electrode 30 and second grounding innerelectrode 50 are arranged on the same insulator layer 12 in theabove-mentioned embodiments, this is not restrictive. For example, thesecond signal inner electrode 30 and second grounding inner electrode 50may be arranged on different insulator layers, i.e., at differentpositions in the laminating direction of the insulator layers 10 to 12.

The number of insulator layers 10 to 12 laminated and the number oflayers to be arranged with the inner electrodes 20, 30, 40, 50 are notlimited to those stated in the above-mentioned embodiments. The forms ofthe inner electrodes 20, 30, 40, 50 are not limited to those describedin the above-mentioned embodiments and modified example.

The number of insulator layers held between the first signal innerelectrode 20 and second grounding inner electrode 50 may be 2 or more,for example, without being restricted to the number stated in theabove-mentioned embodiments. The number of insulator layers held betweenthe second signal inner electrode 30 and second grounding innerelectrode 50 may be 2 or more, for example, without being restricted tothe number stated in the above-mentioned embodiments. The number ofinsulator layers held between the first and second signal innerelectrodes 20, 30 may be 2 or more, for example, without beingrestricted to the number stated in the above-mentioned embodiments.

The numbers of the signal terminal electrodes 1A to 1D, 2A to 2D, andgrounding terminal electrodes 3, 4 are not limited to those stated inthe above-mentioned embodiments. For example, it will be sufficient ifthe first and second signal terminal electrodes are provided by at leasttwo each.

Though the first and second signal terminal electrodes are arranged onthe same side faces of a capacitor body in the above-mentionedembodiments, it will be sufficient if the terminal electrodes 1A to 1D,2A to 2D, 3, 4 are arranged on the outer surface of the capacitor bodywithout being restricted to the arrangements described in theabove-mentioned embodiments. Therefore, it is not always necessary forthe first and second signal terminal electrodes to be arranged on thesame side faces, for example.

From the invention thus described, it will be obvious that the inventionmay be varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedfor inclusion within the scope of the following claims.

1. A feedthrough multilayer capacitor array having a first lead and asecond lead comprising: a capacitor body; at least two first signalterminal electrodes arranged on an outer surface of the capacitor body;at least two second signal terminal electrodes arranged on the outersurface of the capacitor body; at least one first grounding terminalelectrode arranged on the outer surface of the capacitor body; and atleast one second grounding terminal electrode arranged on the outersurface of the capacitor body; wherein: the capacitor body has aplurality of insulator layers laminated, first and second signal innerelectrodes, and first and second grounding inner electrodes; the firstsignal inner electrode is connected to the at least two first signalterminal electrodes; the second signal inner electrode is connected tothe at least two second signal terminal electrodes; the first groundinginner electrode is connected to the at least one first groundingterminal electrode; the second grounding inner electrode is connected tothe at least one second grounding terminal electrode; the first signalinner electrode and second grounding inner electrode include respectiveportions opposing each other while holding therebetween at least one ofthe plurality of insulator layers; the second signal inner electrode andfirst grounding inner electrode include respective portions opposingeach other while holding therebetween at least one of the plurality ofinsulator layers; the first and second signal inner electrodes includerespective portions opposing each other while holding therebetween atleast one of the plurality of insulator layers and not holdingtherebetween any of the inner electrodes; one of the at least two firstsignal terminal electrodes and one of the at least two second signalterminal electrodes are arranged on the same side face in the outersurface of the capacitor body; the other of the at least two firstsignal terminal electrodes and the other of the at least two secondsignal terminal electrodes are arranged on a same side face in the outersurface of the capacitor body; both of the at least two first signalterminal electrodes are connected to the first lead; both of the atleast two second signal terminal electrodes are connected to the secondlead; the first and second signal terminal electrodes arranged on thesame side face are connected to the first and second lead respectivelyso as to be heteropolar; the first grounding terminal electrode isarranged on a side face other than the side faces on which the first andsecond signal terminal electrodes are arranged and is not arranged onthe side faces on which the first and second signal terminal electrodesare arranged; and the second grounding terminal electrode is arranged ona side face other than the side faces on which the first and secondsignal terminal electrodes are arranged and is not arranged on the sidefaces on which the first and second signal terminal electrodes arearranged.
 2. The feedthrough multilayer capacitor array according toclaim 1, wherein: the first signal inner electrode and first groundinginner electrode are arranged on the same insulator layer in theplurality of insulator layers; the second signal inner electrode andsecond grounding inner electrode are arranged on the same insulatorlayer in the plurality of insulator layers; and the insulator layerhaving the first signal inner electrode and first grounding innerelectrode arranged thereon and the insulator layer having the secondsignal inner electrode and second grounding inner electrode arrangedthereon differ from each other.
 3. The feedthrough multilayer capacitorarray according to claim 1, wherein the at least one insulator layerheld between the first signal inner electrode and second grounding innerelectrode, the at least one insulator layer held between the secondsignal inner electrode and first grounding inner electrode, and the atleast one insulator layer held between the first and second signal innerelectrodes are the same.
 4. The feedthrough multilayer capacitor arrayaccording to claim 1, wherein: one of the at least two first signalterminal electrodes and one of the at least two second signal terminalelectrodes are arranged on the same side face in the outer surface ofthe capacitor body; and the other of the at least two first signalterminal electrodes and the other of the at least two second signalterminal electrodes are arranged on the same side face in the outersurface of the capacitor body.
 5. The feedthrough multilayer capacitorarray according to claim 1, wherein: at least three each of the firstand second signal terminal electrodes are provided; the first signalinner electrode is connected to the at least three first signal terminalelectrodes; and the second signal inner electrode is connected to the atleast three second signal terminal electrodes.
 6. The feedthroughmultilayer capacitor array according to claim 1, further comprisingthird and fourth leads, wherein: the first lead is connected to thethird lead at two different points; and the second lead is connected tothe fourth lead at two different points.